<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		红<select id="rSel"></select>
		绿<select id="gSel"></select>
		蓝<select id="bSel"></select>
		<script type="text/javascript">
			
			
			// 练习2
			// 参考练习1
			// 1. 给3个select添加 0-255的选项
			// 2. 添加onchange事件
			//    根据下拉框的值修改网页背景
			
			// document.body.style.background = "red";
			// document.body.style.background = "#00ff00";
			// var r = rSel.value;
			// var g = gSel.value;
			// var b = bSel.value;
			// document.body.style.background = "rgb("+r+","+g+","+b+ ")";
		</script>
	</body>
</html>
